7.3.5.3   Autopilot basic functionality

 

Types of automatic flying:

There are three autopilot modes types:

-    The BASIC modes allow basic flight maneuvers in all dimensions.

-    The RADIO NAVIGATION modes enable to capture and follow simulated radio navigation aids from the navigation database.

-    The FLIGHT PLAN modes control the flight based on the defined or loaded flight plan.

 

Autopilot mode states:

For each autopilot mode one or more states are applicable. The following states exist:

States

Description

select/hold

Autopilot modes that offer these two states allow setting a target value which immediately becomes effective. Any previously active mode of the same channel is immediately deactivated.

arm/capture/ hold

Autopilot modes that have these three states require the selection of a target first, which needs to be approached using another mode of the same channel. Initially these modes are in armed state. The target is then automatically captured (with a soft transition), the previous mode becomes deactivated and the previously armed mode is put in the hold state.

activate

These modes have no target value and are just activated. The mode, which was active before for the same channel is immediately deactivated.

 

Autopilot channels:

The FlightZoomer autopilot modes all belong to one of the three processing channels LATERAL, VERTICAL and SPEED. These channels are processed largely independently, so you can e.g. follow a planned route laterally with the LNAV mode but fly any vertical profile using the four basic vertical modes ALT, VS, FPA or FLCH.

 

Autopilot mode compositions:

If the autopilot is engaged, one mode needs to be active for each channel. Additionally, for the two channels LATERAL and VERTICAL, a second mode can be in the armed state.

As a result, the two channels LATERAL and VERTICAL basically are composite channels which at any time can have one or two modes: At least one which is in the hold or activate state, and optionally a second one which is in the armed state. Some typical cases are explained int the tables below.

The notation is <active mode> + <armed mode>

These are some typical LATERAL composite combinations:

Possible combinations with both active and armed modes

TRK + LOC

Fly Track Over Ground and capture a VOR radial:

Using the TRK mode, the radial of an armed radio navigation aid (VOR) can be approached. The moment, it is reached, the LOC mode becomes active.

TRK + APP

Fly Track Over Ground and capture the ILS:

Using the TRK mode, the localizer of an armed ILS approach can be approached. The moment, the current track intersects the localizer, the APP mode becomes active.

Note: the lateral and the vertical channel of the APP mode also work independently: the localizer and the glideslope don’t need to be captured in the same moment. Instead, each is captured as soon as it is reached.



These are some typical VERTICAL composite combinations:

Possible combinations with both active and armed modes

VS + ALT

Fly in Vertical Speed mode and capture the armed altitude

While climbing or descending with the VS mode, an altitude can be armed, which will be captured the moment it is reached.

The automatic transition to ALT after reaching the target altitude is not only possible coming from VS, but also coming from FPA or FLCH.

ALT + APP

Fly in Altitude hold mode and capture the ILS glideslope

While flying in active ALT hold mode, the ILS can be armed, so the glideslope will be captured the moment it is intersected.

The automatic transition to APP while capturing the glideslope is not only possible coming from ALT, but also coming from VS  or FPA.

 

See in the following sections, how all this dry theory supports intuitive and easy flight operations!